Such a rubber injection press is commercially available in horizontal and vertical design and is for example known from the firm leaflet "WERNER & PFLEIDERER Gummitechnik" VF 04 044/1-3.0+3.0-VIII.80 GM. In this press rubber is plasticized in a plasticization unit after the joining and closing of the mould and is injected into the mould pockets by means of an injection unit and through corresponding injection channels or injection nozzles, respectively, in the clamping table, through the heating panel and the corresponding stationary mould elements. Then both mould elements are heated by means of a corresponding heating panel, so that the vulcanizing process can take place. The heating elements in the heating panel are in the form of so-called heating cartridges, which are inserted into corresponding bores of the heating panel. It is of disadvantage that the heat transfer between the heating cartridge and the heating panel is comparatively bad. Further, there is a considerable risk of collision between the straight-lined heating cartridges and other parts possibly necessary in terms of design, such as clamping elements, whereby the possible design regarding the arrangement of the heating cartridges is further restricted. A non-uniform heat transfer from the respective heating cartridge to the heating panel is further caused by dimensional tolerances, which may in turn result in local overheatings and thus also in a breakdown of the heating cartridges.
A press plate for a vulcanizing press is known from German published patent application 25 27 181. This press plate consists of a heating panel formed as an extrusion component and provided with bracing webs extending parallel to one another. A cover plate is put onto these bracing webs. These components consist of light metal. Any optional heating elements in the form of panel heaters, heating tubes, heating foils or the like are inserted in the hollow space between neighbouring bracing webs. It is rather doubtful whether the heat transfer to the press plate is satisfactory.
A heating plate is known from British patent 4672 of 1909 comprising a plate provided to emit heat, a so-called hot plate, and an insulated plate. A heating in the form of a spiral is arranged in a hollow space between the two plates and is to heat the so-called hot plate inductively and by radiation. The disadvantages outlined above apply to this design, too.